I was killing time, launched the steam client and noticed I had a 400MB L4D2 update cued up. It's a 'community' made thing with new maps and new skins (maybe other stuff, haven't really looked into the details). So I had lost interest in this a couple of years ago at least, but I decided to give this one a go account of free, and small dl.
“This Rat Covers Itself With Poison That Can Take Out an Elephant”